Spinal connectors and related methods

ABSTRACT

In some embodiments, a connector can be configured to couple a first fixation element (e.g., a first rod) to a second fixation element (e.g., a second rod). One or both of the first and second fixation elements can be included with the connector, or one or both can be separately provided. In some instances, at least one of the fixation elements is previously implanted in a patient. The connector can provide one or more degrees of freedom between the first and second fixation elements. The connector can also include a locking element configured to (1) lock one or more of the fixation elements to the connector, and (2) lock one or more of the degrees of freedom between the fixation elements. The connector can be configured to snap onto or otherwise engage a fixation element in a manner that provides tactile and/or audible feedback to the surgeon.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/496,804 filed on Sep. 25, 2014, which is hereby incorporated byreference herein.

FIELD

Spinal implant connectors and related methods are disclosed herein.

BACKGROUND

Fixation systems can be used in orthopedic surgery to align and/or fix adesired relationship between two or more bones or bone fragments. Forexample, in spinal surgery, spinal fixation systems can be used to alignand/or fix a desired relationship between vertebral bodies. Such devicestypically include a spinal fixation element, such as a relatively rigidfixation rod, that is coupled to the vertebrae by attaching the elementto various anchoring devices, such as hooks, bolts, wires, or screws.The fixation element can have a predetermined or adjustable contourselected based on the desired correction or fixation. Once installed,the fixation element holds the vertebrae in a desired spatialrelationship, either until desired healing or spinal fusion has takenplace, or for some other period of time.

There are a number of instances in which it can be desirable to couplemultiple spinal fixation elements to each other. For example, variousaspects of the patient's anatomy, the surgical technique used, and/orthe desired correction can require multiple spinal rods to be coupled toone another. By way of further example, there can be a desire in somerevision surgeries to extend a previously-installed construct toadditional vertebral levels by coupling a newly-installed spinal rod toa previously-installed rod. As yet another example, coupling multiplerods to one another can improve the overall strength and stability of animplanted construct.

Minimally-invasive surgical techniques have been developed to facilitateinstallation of spinal fixation systems via one or more percutaneousworking channels, thereby reducing patient trauma and recovery time.These techniques, however, are often not well-suited for installingmultiple fixation elements which are to be coupled to one another, orfor coupling a new fixation element to a previously-installed constructduring revision surgery. Even in open surgery, existing systems forcoupling multiple fixation elements to one another can be cumbersome anddifficult to use. Accordingly, a need exists for improved spinalconnectors and related methods.

SUMMARY

In some embodiments, a connector can be configured to couple a firstfixation element (e.g., a first rod) to a second fixation element (e.g.,a second rod). One or both of the first and second fixation elements canbe included with the connector, or one or both can be separatelyprovided. In some instances, at least one of the fixation elements ispreviously implanted in a patient. The connector can provide one or moredegrees of freedom between the first and second fixation elements. Theconnector can also include a locking element configured to (1) lock oneor more of the fixation elements to the connector, and (2) lock one ormore of the degrees of freedom between the fixation elements. Theconnector can be configured to snap onto or otherwise engage a fixationelement in a manner that provides tactile and/or audible feedback to thesurgeon. At least one of the fixation members can include a bend or jogto provide clearance for patient anatomy or for components of a fixationconstruct to which the connector is to be attached. The connector can beused in various surgical methods, including minimally-invasive revisionprocedures in which an existing spinal fixation construct is extended toone or more additional vertebral levels.

In some embodiments, a spinal connector includes a first spinal fixationelement having a mating feature that defines an opening and a connectionassembly coupled to the mating feature such that at least a portion ofthe connection assembly is received within the opening of the matingfeature. The connection assembly can include a clamp that defines arecess configured to receive a second spinal fixation element and alocking element configured to selectively lock the clamp to the secondspinal fixation element and to lock one or more degrees of freedom ofthe connection assembly.

The one or more degrees of freedom can include a first rotational degreeof freedom by which the first spinal fixation element is rotatable withrespect to the clamp about a longitudinal axis of the opening and asecond rotational degree of freedom by which the first spinal fixationelement is rotatable with respect to the clamp about a transverse axisof the opening. The clamp can include an elongate stud portionconfigured to extend through the opening of the mating feature of thefirst spinal fixation element such that the stud portion can rotateabout a longitudinal axis of the opening and such that the stud portioncan rotate about a transverse axis of the opening. The locking elementcan include a locking nut configured to threadably engage a stud portionof the clamp. The connection assembly can include a washer disposedaround the stud portion of the clamp between the locking nut and themating feature of the first spinal fixation element. The washer caninclude first and second recesses having teeth formed therein configuredto mesh with corresponding teeth formed on first and second protrusionsformed on the mating feature when the protrusions are at least partiallyreceived within the recesses. The clamp can include first and secondarms coupled to one another at a hinge portion and an outer surface ofthe clamp can be tapered such that advancement of the locking elementalong a longitudinal axis of the clamp is effective to squeeze the armsof the clamp together. The hinge portion can include a living hinge. Thespinal connector can include a coupling member extending outward fromthe mating feature and configured to couple the first spinal fixationelement to an insertion device. The clamp can be configured to provideat least one of audible and tactile feedback when a second spinalfixation element is received in the recess. The first spinal fixationelement can include a first elongate portion, a second elongate portionthat is parallel to the first elongate portion and offset from the firstelongate portion in one or more dimensions, and an intermediate portionconnecting the first and second elongate portions. The intermediateportion can be shaped to bend around a bone anchor coupled to the secondspinal fixation element when the clamp is attached to the second spinalfixation element. The mating feature can include a ring-shaped bodyformed integrally with the first spinal fixation element. The openingcan include reliefs formed in an inner surface thereof to facilitateangulation of the clamp within the opening. The mating feature canextend longitudinally from an end portion of the first spinal fixationelement. The mating feature can extend laterally from an end portion ofthe first spinal fixation element. The connection assembly can include ahousing having first and second shoes slidably disposed therein, thelocking element being configured to push the first shoe into engagementwith the mating feature to lock an orientation of the first spinalfixation element relative to the housing and to push the second shoeinto engagement with the second spinal fixation element to lock thesecond spinal fixation element in the clamp. The clamp can include anupper clamping arm and a lower clamping arm with a biasing elementdisposed therebetween, the locking element extending through openingsformed in the upper clamping arm, the biasing element, and the lowerclamping arm. The one or more degrees of freedom can include arotational degree of freedom by which the first spinal fixation elementis rotatable with respect to the upper and lower clamping arms about alongitudinal axis of the locking element.

In some embodiments, a spinal connector includes a clamp having firstand second arms configured to grasp a spinal fixation element, at leasta portion of the first and second arms defining a stud portion; a spinalfixation element having a mating feature that defines an opening throughwhich the stud portion of the clamp extends; and a locking elementconfigured to engage the stud portion to selectively move the first andsecond arms toward one another and to lock rotation of the stud portionabout a longitudinal axis of the opening and about a transverse axis ofthe opening.

The locking element can include a locking nut configured to threadablyengage the stud portion of the clamp. The spinal connector can include awasher disposed around the stud portion of the clamp between the lockingnut and the mating feature of the spinal fixation element. The washercan include first and second recesses having surface features formedtherein configured to mesh with corresponding surface features formed onfirst and second protrusions formed on the mating feature when theprotrusions are at least partially received within the recesses. Thefirst and second arms can be coupled to one another at a hinge portionand an outer surface of the clamp can be tapered such that advancementof the locking element along a longitudinal axis of the clamp iseffective to squeeze the arms of the clamp together.

In some embodiments, a spinal connector includes a first elongate rodhaving a first section that is parallel to and offset from a secondsection, the first and second sections being joined by a transitionsection; a ring-shaped mating feature extending from the first sectionof the rod; a clamp having first and second clamping arms that define arecess therebetween in which a second elongate rod can be received, theclamp having a stud portion that extends through a central opening ofthe ring-shaped mating feature such that the mating feature bearsagainst a shoulder of the stud portion and such that the stud portion isrotatable about a longitudinal axis of the central opening and about atransverse axis of the central opening; a washer disposed over the studportion; and a locking nut threadably-engaged with the stud portion suchthat the washer is disposed between the locking nut and the matingfeature and such that the mating feature is disposed between the washerand the shoulder. Tightening the locking nut can be effective to lockrotation of the stud portion about the longitudinal and transverse axesof the central opening and to squeeze the first and second clamping armstogether to lock the clamp to a second elongate rod disposed in therecess.

One of the washer and the mating feature can include a curved recess inwhich a plurality of teeth are formed, the plurality of teeth beingconfigured to engage a plurality of teeth formed on a curved protrusionformed on the other of the washer and the mating feature when theprotrusion is at least partially received within the recess.

In some embodiments, a spinal connector includes a first clamping memberthat defines a recess configured to receive a first spinal fixationelement; a second clamping member that defines a recess configured toreceive a second spinal fixation element; and a locking element thatextends through openings formed in the first and second clampingmembers, the locking element being configured to selectively lock thefirst clamping member to the first spinal fixation rod, lock the secondclamping member to the second spinal fixation rod, and lock one or moredegrees of freedom between the first and second clamping members.

The one or more degrees of freedom can include a rotational degree offreedom by which the first clamping member is rotatable with respect tothe second clamping member about a longitudinal axis of the lockingelement and a translational degree of freedom by which the firstclamping member is translatable with respect to the second clampingmember along an axis that extends perpendicular to the longitudinal axisof the locking element. The second clamping member can be rotatablerelative to the first clamping member about a longitudinal axis of thelocking element when the locking element is in an unlockedconfiguration. The second clamping member can be translatable relativeto the first clamping member along an axis that extends perpendicular tothe longitudinal axis of the locking element when the locking element isin an unlocked configuration.

In some embodiments, a spinal fixation method includes forming a firstminimally-invasive pathway to access a first vertebra; delivering ascrew through the first minimally-invasive pathway; implanting the screwin the first vertebra; forming a second minimally-invasive pathway toaccess a first spinal fixation element coupled to at least one othervertebra; delivering a second spinal fixation element and a spinalconnector coupled thereto through the second minimally-invasive pathway;moving the spinal connector relative to the second spinal fixationelement about one or more degrees of freedom to position at least aportion of the second spinal fixation element in engagement with thescrew; and actuating a locking element of the spinal connector to lockthe spinal connector to the first spinal fixation element and to lockthe one or more degrees of freedom.

Moving the spinal connector can include moving the second spinalfixation element subcutaneously into engagement with the screw. Thefirst spinal fixation element can be a previously-implanted spinalfixation element. The spinal connector can include a clamp having a studportion that extends through an opening of a mating feature of thesecond spinal fixation element, and the one or more degrees of freedomcan include a first rotational degree of freedom by which the secondspinal fixation element is rotatable with respect to the clamp about alongitudinal axis of the opening and a second rotational degree offreedom by which the second spinal fixation element is rotatable withrespect to the clamp about a transverse axis of the opening. The spinalconnector can include a clamp having a stud portion that extends throughan opening of a mating feature of the second spinal fixation element,and moving the spinal connector can include pivoting the stud portionabout a longitudinal axis of the central opening and about a transverseaxis of the central opening. The spinal connector can include a clamphaving a stud portion that extends through an opening of a matingfeature of the second spinal fixation element, and actuating the lockingelement can include tightening a locking nut that is threadably engagedwith the stud portion to compress the mating feature against a shoulderof the stud portion. The spinal connector can include a clamp having astud portion that extends through an opening of a mating feature of thesecond spinal fixation element and a washer disposed around the studportion, and moving the spinal connector can include engaging surfacefeatures formed on the washer with corresponding surface features formedon the mating feature. The spinal connector can include first and secondarms coupled to one another at a hinge portion and having tapered outersurfaces, and actuating the locking element can include advancing alocking nut along the first and second arms to squeeze the armstogether. Actuating the locking element can consist only of rotating asingle locking element. The method can include positioning the secondspinal fixation element such that the second spinal fixation elementextends around a bone anchor secured to the first spinal fixationelement. The method can include attaching the spinal connector to thefirst spinal fixation element at a location intermediate first andsecond bone anchors securing the first spinal fixation element to bone.

In some embodiments, a spinal fixation method includes forming a firstminimally-invasive pathway to access a first vertebra; delivering ascrew through the first minimally-invasive pathway; implanting the screwin the first vertebra; forming a second minimally-invasive pathway toaccess a first spinal fixation element coupled to at least one othervertebra; delivering a second spinal fixation element through the firstminimally-invasive pathway to position a portion of the second spinalfixation element in the second minimally-invasive pathway; inserting aspinal connector through the second minimally-invasive pathway andcoupling the spinal connector to the first and second spinal fixationelements; and securing the second spinal fixation element to the screw.

Coupling the spinal connector can include adjusting one or more degreesof freedom of the spinal connector to position the spinal connector withrespect to the first and second spinal fixation elements; and actuatinga locking element of the spinal connector to lock the spinal connectorto the first and second spinal fixation elements and to lock the one ormore degrees of freedom.

In some embodiments, a spinal fixation method includes clamping a spinalconnector having a first spinal fixation element coupled thereto onto asecond spinal fixation element; and actuating a locking mechanism of thespinal connector to simultaneously lock the spinal connector to thesecond spinal fixation element and to lock one or more degrees offreedom between the spinal connector and the first spinal fixationelement.

The present invention further provides devices and methods as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a perspective view of a spinal connector coupled to a spinalfixation element;

FIG. 1B is another perspective view of the spinal connector and thespinal fixation element of FIG. 1A;

FIG. 1C is an exploded perspective view of the spinal connector of FIG.1A;

FIG. 1D is another exploded perspective view of the spinal connector ofFIG. 1A;

FIG. 1E is a sectional, partially-exploded, profile view of the spinalconnector of FIG. 1A with a spinal fixation element component of theconnector omitted;

FIG. 2A is a perspective view of another spinal connector;

FIG. 2B is a profile view of the spinal connector of FIG. 2A;

FIG. 2C is a plan view of the spinal connector of FIG. 2A coupled tofirst and second spinal fixation elements;

FIG. 2D is another plan view of the spinal connector of FIG. 2A coupledto first and second spinal fixation elements;

FIG. 2E is a perspective view of a second clamping member of the spinalconnector of FIG. 2A;

FIG. 2F is a perspective view of a first clamping member of the spinalconnector of FIG. 2A;

FIG. 2G is an exploded perspective view of the spinal connector of FIG.2A;

FIG. 2H is a profile view of the spinal connector of FIG. 2A with analternate recess shape;

FIG. 3A is a perspective view of another spinal connector;

FIG. 3B is an exploded perspective view of the spinal connector of FIG.3A;

FIG. 3C is another exploded perspective view of the spinal connector ofFIG. 3A;

FIG. 3D is a plan view of the spinal connector of FIG. 3A coupled to aspinal fixation element;

FIG. 3E is another plan view of the spinal connector of FIG. 3A coupledto a spinal fixation element;

FIG. 4A is a perspective view of another spinal connector;

FIG. 4B is an exploded perspective view of the spinal connector of FIG.4A;

FIG. 4C is another exploded perspective view of the spinal connector ofFIG. 4A;

FIG. 4D is a plan view of the spinal connector of FIG. 4A coupled to aspinal fixation element;

FIG. 4E is a perspective view of the spinal connector of FIG. 4A with analternative coupling feature;

FIG. 5A is a perspective view of another spinal connector;

FIG. 5B is an exploded perspective view of the spinal connector of FIG.5A;

FIG. 5C is a profile view of the spinal connector of FIG. 5A coupled toa spinal fixation element;

FIG. 5D is a plan view of the spinal connector of FIG. 5A coupled to aspinal fixation element in another orientation; and

FIGS. 6A-6G schematically illustrate a spinal fixation method.

DETAILED DESCRIPTION

In some embodiments, a connector can be configured to couple a firstfixation element (e.g., a first rod) to a second fixation element (e.g.,a second rod). One or both of the first and second fixation elements canbe included with the connector, or one or both can be separatelyprovided. In some instances, at least one of the fixation elements ispreviously implanted in a patient. The connector can provide one or moredegrees of freedom between the first and second fixation elements. Theconnector can also include a locking element configured to (1) lock oneor more of the fixation elements to the connector, and (2) lock one ormore of the degrees of freedom between the fixation elements. Theconnector can be configured to snap onto or otherwise engage a fixationelement in a manner that provides tactile and/or audible feedback to thesurgeon. At least one of the fixation members can include a bend or jogto provide clearance for patient anatomy or for components of a fixationconstruct to which the connector is to be attached. The connector can beused in various surgical methods, including minimally-invasive revisionprocedures in which an existing spinal fixation construct is extended toone or more additional vertebral levels.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of skilled in the art will understand that the devicesand methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

FIGS. 1A-1E illustrate an exemplary embodiment of a spinal connector100. The connector 100 generally includes a first spinal fixationelement 102 and a connection assembly 104 for coupling the first spinalfixation element 102 to a second spinal fixation element 106. The secondspinal fixation element 106 can be a previously-implanted spinalfixation element to which the connector 100 is to be coupled or can beimplanted with the connector 100 or as part of the same procedure as theconnector 100. The connection assembly 104 can include a lockingmechanism for selectively locking an orientation of the first spinalfixation element 102 relative to the connection assembly 104 and forlocking a position and an orientation of the connection assemblyrelative to the second spinal fixation element 106. As shown, theconnection assembly 104 can include a housing 108, a set screw 110,first and second shoes 112, 114, and a retaining cap 116.

In the illustrated embodiment, the first and second spinal fixationelements 102, 106 are elongate spinal rods, though it will beappreciated that any of a variety of fixation elements can be usedinstead or in addition, such as bone plates. The first spinal fixationelement 102 can include a mating feature 118 formed on or coupled to afirst terminal end thereof configured to rotatably couple the firstspinal fixation element to the housing 108. In the illustratedembodiment, the mating feature 118 is a ring-shaped structure formedintegrally with the first spinal fixation element 102. The matingfeature 118 can include a central opening 120 configured to receive apost 122 that extends laterally-outward from the housing 108 such thatthe mating feature is rotatable about the post (e.g., about alongitudinal axis of the post). Stated differently, the housing 108 canbe rotatable about a longitudinal axis A1 of the central opening 120. Asecond, opposite terminal end 124 of the first spinal fixation element102 can be configured to facilitate minimally-invasive insertion of thefirst spinal fixation element. For example, the second terminal end 124can be rounded, bulleted, tapered, etc. to allow for atraumatictunneling of the first spinal fixation element 102 subcutaneously froman insertion portal to a final implanted position.

The first spinal fixation element 102 can be completely straight or caninclude one or more bends, curves, joints, offsets, jogs, etc. Forexample, the first spinal fixation element 102 can have an S-shaped orZ-shaped bend to provide clearance for patient anatomy or for a portion(e.g., a bone screw) of a fixation construct to which the connector 100is to be coupled. In the illustrated embodiment, the first spinalfixation element 102 includes a straight portion 126 joined by a curvedportion 128 to the mating feature 118. The curved portion 128 canprovide an offset such that the first spinal fixation element 102 canbend around a portion of the patient's anatomy or a portion of afixation construct to which the connector 100 is coupled. Accordingly, alow-profile construct can be formed, with the straight portion 126 ofthe first spinal fixation element 102 positioned as a natural extensionof the second spinal fixation element 106. It will thus be appreciatedthat the connector 100 can be clamped onto a previously-installed secondspinal fixation element 106, intermediate to first and second boneanchors securing the second spinal fixation element, without the firstspinal fixation element 102 interfering with the bone anchors. The firstspinal fixation element 102 can be rigid, can be bendable or malleable,or can include both rigid portions and bendable portions. Thus, in someembodiments, the contour of the first spinal fixation element 102 can beadjusted as needed for a particular procedure, either manually or withthe assistance of bending tools.

The retaining cap 116 can be configured to retain the mating feature 118of the first spinal fixation element 102 on the post 122 of the housing108, while still allowing the first spinal fixation element to rotateabout the post. The retaining cap 116 can include a disc-shaped cover130 with a pin 132 extending therefrom. The pin 132 can be receivedwithin the post 122 of the housing 108 to capture the mating feature 118between the housing and the cover 130. The exterior of the pin 132 andthe interior of the post 122 can include corresponding threads tothreadably engage one another. While a threaded engagement is shown, itwill be appreciated that any of a variety of other techniques can beused to couple the retaining cap 116 to the housing 108. For example,the pin 132 can be press-fit, welded, cross-pinned, and/or glued to thepost 122.

The housing 108 can include a clamp portion 134 in which the secondspinal fixation element 106 can be received. The clamp portion 134 canbe formed on a side of the housing 108 opposite to the side of thehousing from which the post 122 extends. Alternatively, the clampportion 134 can be formed on a side of the housing adjacent to the sidefrom which the post 122 extends.

The clamp portion 134 can include a recess 136 sized and/or shapedaccording to the second spinal fixation element 106 to which theconnector 100 is to be coupled. For example, a diameter of the recess136 can be substantially equal to a diameter of the second spinalfixation element 106. Alternatively, the diameter of the recess 136 canbe slightly less than the diameter of the second spinal fixation element106 to allow for a snap-fit engagement that provides tactile and/oraudible feedback to the surgeon when the connector 100 “snaps” onto thesecond spinal fixation element. As discussed further below, thisfeedback can be advantageous, particularly in minimally-invasiverevision surgery. As another alternative, the diameter of the recess 136can be slightly greater than that of the second spinal fixation element106, with any play being taken up by the second shoe 114 when thelocking mechanism of the connector 100 is actuated, as described below.The spinal connector 100 can thus be configured to couple to secondspinal fixation elements of various sizes or shapes. In someembodiments, a plurality of spinal connectors 100, each having recesses136 with different sizes or shapes, can be provided as part of a kit toallow for selection of a connector sized and shaped appropriately for aparticular application.

While the illustrated recess 136 forms a portion of a cylinder, it willbe appreciated that the recess can have various other shapes dependingon the shape of the second spinal fixation element 106 to which theconnector 100 is to be coupled. For example, in the case of a secondspinal fixation element 106 with a rectangular cross-section, the recess136 can have a corresponding rectangular shape.

The recess 136 can have a longitudinal axis A2 that extendsperpendicular to the longitudinal axis A1 of the central opening 120.Thus, the longitudinal axis A2 of the recess 136 can be perpendicular toa rotation axis about which the first spinal fixation element 102rotates relative to the housing 108. In such embodiments, when a secondspinal fixation element 106 is received in the recess 136, the firstspinal fixation element 102 can be rotatable about an axis perpendicularto a longitudinal axis of the second spinal fixation element 106. Theclamp portion 134 of the housing 108 that defines the recess 136 can beconfigured to extend around any portion of the second spinal fixationelement 106. In the illustrated embodiment, the clamp portion 134 issized to extend around approximately 200 degrees of the circumference ofthe second spinal fixation element 106. In other embodiments, the clampportion 134 can cover a greater or lesser extent of the circumference ofthe second spinal fixation element 106. For example, the extent ofcoverage can be between about 160 degrees and about 240 degrees of thecircumference of the second spinal fixation element 106.

The housing 108 can include an opening in which a locking element isreceived. For example, as shown, the housing 108 can include aninternally-threaded bore hole 138 configured to receive anexternally-threaded set screw 110. As best seen in FIG. 1E, the housing108 can also include first and second channels 140, 142 in which thefirst and second shoes 112, 114 are slidably received, respectively. Thefirst channel 140 can extend from the threaded bore hole 138 to asidewall opening 144 formed in the post 122. As best shown in FIG. 1D,the second channel 142 can be open to the recess 136 and can extend fromthe recess to the threaded bore hole 138.

The first shoe 112 can be slidable within the first channel 140 betweenan extended position in which the first shoe protrudes through the post122 and a retracted position in which the first shoe does not protrudethrough the post or protrudes though the post to a lesser extent. In theextended position, the first shoe 112 can engage the interior sidewallof the mating feature 118 to resist or prevent rotation of the firstspinal fixation element 102 about the post 122. In the retractedposition, the first shoe 112 does not engage, or only lightly-engages,the mating feature 118 such that the first spinal fixation element 102is freely-rotatable about the post 122. The surface of the first shoe112 configured to engage the mating feature 118 can include teeth,serrations, or other gripping features or surface treatments to provideenhanced purchase with the mating feature. An opposite surface of thefirst shoe 112 configured to be engaged by the locking element can beshaped to match the shape of the locking element and to encouragesliding movement of the first shoe as the locking element is advancedwithin the opening 138. For example, the first shoe 112 can define aramped or concave surface 146 sized to match a convex distal tip 148 ofthe locking element 110.

The second shoe 114 can be slidable within the second channel 142between an extended position in which the second shoe protrudes into therecess 136 and a retracted position in which the second shoe does notprotrude into the recess or protrudes into the recess to a lesserextent. In the extended position, the second shoe 114 can engage asecond spinal fixation element 106 disposed within the recess 136 toclamp the connector 100 to the second spinal fixation element, resistingor preventing relative movement between the two (e.g., rotation and/orlongitudinal translation). In the retracted position, the second shoe114 does not interfere with positioning of a second spinal fixationelement 106 within the recess 136 and allows the connector 100 to beslid along the second spinal fixation element 106 to a desired locationand rotated about the second spinal fixation element 106 to a desiredorientation. The surface of the second shoe 114 configured to engage thesecond spinal fixation element 106 can be shaped in accordance with atype of the second spinal fixation element. For example, when theconnector 100 is to be coupled to a cylindrical fixation rod, thesurface can have a radius of curvature that matches the radius of therod, or that substantially matches (i.e., is slightly less than orgreater than) the radius of the rod. The surface can include teeth,serrations, or other gripping features or surface treatments to provideenhanced purchase with the second spinal fixation element 106. Anopposite surface of the second shoe 114 configured to be engaged by thelocking element can be shaped to match the shape of the locking elementand to encourage sliding movement of the second shoe as the lockingelement is advanced within the opening 138. For example, the second shoe114 can define a ramped or concave surface 150 sized to match a convexdistal tip 148 of the locking element 110.

The housing 108 can include one or more retention pins 152 configured tolimit the travel of the first and/or second shoes 112, 114 (e.g., toprevent the shoes from inadvertently falling out of the connector 100).In the illustrated embodiment, the pins 152 extend into the first andsecond channels 140, 142 of the housing 108 and are slidably receivedwithin slots or grooves 154 formed in the first and second shoes 112,114.

As the locking element 110 is advanced within the opening, it can engagethe first shoe 112 and cause the first shoe to slide within the firstchannel 140 into engagement with the interior sidewall of the matingfeature 118 of the first spinal fixation element 102. Simultaneously,the locking element 110 can engage the second shoe 114 and cause thesecond shoe to slide within the second channel 142 into engagement witha second spinal fixation element 106 disposed within the recess 136. Inthe illustrated embodiment, the first and second channels 140, 142extend downward and laterally-outward from the opening 138 such that thefirst and second shoes 112, 114 translate along linear paths between theretracted and extended positions. In other embodiments, one or both ofthe first and second channels 140, 142 can extend only downwardly oronly outwardly. In still further embodiments, the first and second shoes112, 114 can be configured to rotate between the extended and retractedpositions without linear translational movement or in combination withlinear translational movement. For example, the first and second shoes112, 114 can be mounted on respective pivot pins such that they arerotatable relative to the housing 108 between the extended and retractedpositions.

While any of a variety of locking elements can be used, in theillustrated embodiment, the locking element comprises an externallythreaded set screw 110. The set screw 110 can threadably engagecorresponding interior threads of the opening 138 such that rotation ofthe set screw in a first direction is effective to advance the set screwinto the housing 108 and rotation of the set screw in a second, oppositedirection is effective to withdraw the set screw relative to thehousing. A longitudinal axis A3 of the opening can extend perpendicularto the longitudinal axis A2 of the recess and perpendicular to arotation axis of the first spinal fixation element 102 about the post122 (e.g., to the longitudinal axis A1 of the central opening 120). Thelength of the set screw 110 can be substantially equal to the depth ofthe opening 138 such that, when fully-seated in the opening, the topsurface of the set screw sits flush with the top surface of the housing108. The set screw 110 can include a driving interface 156 configured toreceive or engage a screwdriver, wrench, or other instrument forrotating the set screw. The distal tip 148 of the set screw 110 caninclude an engagement surface for engaging the first and second shoes112, 114. For example, the distal tip 148 of the set screw 110 can beconical, tapered, bulleted, convex, etc. to provide a camming surfacethat bears against the first and second shoes 112, 114 to urge the shoestowards their respective extended positions. While a single set screw110 is shown, it will be appreciated that the connector 100 can includea plurality of set screws (e.g., a first set screw configured to engagethe first shoe 112 and selectively lock rotation of the first spinalfixation element 102 relative to the housing 108 and a second set screwconfigured to engage the second shoe 114 and selectively clamp thehousing 108 to the second spinal fixation element 106).

In use, the spinal connector 100 can be positioned in a surgical site(e.g., using a minimally-invasive technique as described in detailbelow). A previously-placed second spinal fixation element 106 can bepositioned within the recess 136 and the housing 108 can be moved to adesired position and/or orientation with respect to the second spinalfixation element 106. In addition, the first spinal fixation element 102can be rotated to a desired position. As the set screw 110 is tightened,the first and second shoes 112, 114 can be urged within the first andsecond channels 140, 142 into engagement with the mating feature 118 andthe second spinal fixation element 106, respectively. The first shoe 112can engage the mating feature 118 to lock the rotational position of thefirst spinal fixation element 102 relative to the housing 108. At thesame time or at substantially the same time, the second shoe 114 canengage the second spinal fixation element 106 to clamp the housing 108thereto and lock the position and orientation of the housing 108relative to the second spinal fixation element 106. Actuation of asingle locking mechanism can thus be effective to both (1) lock anorientation of a first spinal fixation element rotatably coupled to theconnector and (2) lock a position and an orientation of the connectorrelative to a second spinal fixation element. This multiplefunctionality of locking onto a second spinal fixation element andlocking one or more degrees of freedom of the connector can beparticularly advantageous in minimally-invasive surgery, as access isonly required to a single locking mechanism and two or more functionscan be performed in a single step.

The spinal connector 100 can be coupled to the second spinal fixationelement 106 in any of a variety of orientations. For example, the spinalconnector 100 can be coupled to the second spinal fixation element 106such that the driving interface 156 of the set screw 110 faces in aposterior direction relative to the patient and such that the set screwis advanced along an anterior-posterior axis to lock the connector. Byway of further example, the spinal connector 100 can be coupled to thesecond spinal fixation element 106 such that the driving interface 156of the set screw 110 faces in a medial or lateral direction relative tothe patient and the set screw is advanced along a medial-lateral axis tolock the connector. The spinal connector 100 can also be coupled to thesecond spinal fixation element 106 in any orientation between the abovetwo examples and at any point along a length of the second spinalfixation element.

FIGS. 2A-2H illustrate another exemplary embodiment of a spinalconnector 200. The connector can include first and second clampingmembers 202, 204 configured to grasp first and second spinal fixationelements 206, 208, respectively. The connector 200 can also include alocking mechanism (e.g., a locking bolt 210 and locking nut 212 asshown) configured to selectively lock the first and second clampingmembers 202, 204 to the first and second spinal fixation elements 206,208 and to lock one or more degrees of freedom of the connector 200.

The first clamping member 202 can include opposed arms 214 coupled toone another at a hinge portion 216. While a living hinge 216 is shown,it will be appreciated that any of a variety of hinge mechanisms can beused. For example, the opposed arms 214 can be rotatably coupled to oneanother about a pivot pin. The opposed arms 214 can each include amating portion 218 in which a recess 220 is formed for receiving a firstspinal fixation element 206. Each of the opposed arms 214 can alsoinclude a main portion 222 disposed between the hinge portion 216 andthe mating portion 218. The opposed arms 214 can be positionable in anunlocked position in which a slot 224 defined between the main portions222 of the arms has substantially parallel sidewalls and in which thefirst clamping member 202 is movable with respect to a first spinalfixation element 206 disposed between the mating portions 218 of thearms. The opposed arms 214 can also be positionable in a locked positionin which the main portions 222 of the arms are deflected towards oneanother about the hinge portion 216 and in which a first spinal fixationelement 206 disposed between the mating portions 218 of the arms islocked to the first clamping member 202 to resist or prevent rotation orsliding movement of the first spinal fixation element relative to thefirst clamping member.

The mating portions 218 can define a recess 220 therebetween sizedand/or shaped according to the first spinal fixation element 206 towhich the first clamping member 202 is to be coupled. For example, adiameter of the recess 220 can be substantially equal to a diameter ofthe first spinal fixation element 206. Alternatively, the diameter ofthe recess 220 can be slightly less than the diameter of the firstspinal fixation element 206 to allow for a snap-fit engagement thatprovides tactile and/or audible feedback to the surgeon when the firstclamping member 202 “snaps” onto the spinal fixation element 206. Asdiscussed further below, this feedback can be advantageous, particularlyin minimally-invasive revision surgery. As another alternative, thediameter of the recess 220 can be slightly greater than that of thefirst spinal fixation element 206 to which the connector 200 is to becoupled, with any play being taken up by the clamping action when thelocking bolt 210 and locking nut 212 are tightened. The first clampingmember 202 can thus be configured to couple to first spinal fixationelements of various sizes or shapes. In some embodiments, a plurality ofclamping members 202, each having recesses 220 with different sizes orshapes, can be provided as part of a kit to allow for selection of aclamping member sized and shaped appropriately for a particularapplication.

While the illustrated recess 220 forms a portion of a cylinder, it willbe appreciated that the recess can have various other shapes dependingon the shape of the first spinal fixation element 206 to which the firstclamping member 202 is to be coupled. For example, in the case of afirst spinal fixation element 206 with a rectangular cross-section, therecess 220 can have a corresponding rectangular shape. As shown in FIG.2H, the recess 220 can be defined by flat or planar sidewalls which, atleast in some instances, can provide increased surface contact for abroader range of fixation element sizes and shapes.

As shown in FIG. 2G, the recess 220 can have a longitudinal axis A1 thatextends perpendicular to a longitudinal axis A2 of the locking bolt 210when the locking bolt extends through the first clamping member 202.Thus, the longitudinal axis A1 of the recess 220 can be perpendicular toa rotation axis A2 about which the first clamping member 202 rotatesrelative to the locking bolt 210. The mating portions 218 of the arms214 can be configured to extend around any portion of the first spinalfixation element 206. In the illustrated embodiment, the arms 214collectively extend around approximately 180 degrees of thecircumference of the first spinal fixation element 206. In otherembodiments, the arms 214 can cover a greater or lesser extent of thecircumference of the first spinal fixation element 206. For example, theextent of coverage can be between about 90 degrees and about 270 degreesof the circumference of the first spinal fixation element 206.

Coaxial openings 226 can be formed in the opposed arms 214 of the firstclamping member 202 such that the locking bolt 210 can extend throughthe opposed arms. The first clamping member 202 can be rotatable about alongitudinal axis A2 of the locking bolt 210 when the locking bolt isdisposed through the opposed arms 214 and before the locking bolt andlocking nut 212 are tightened. One or more internal dimensions of theopenings 226 can be larger than corresponding external dimensions of thelocking bolt 210 to allow the first clamping member 202 to translate inone or more directions relative to the locking bolt when the lockingbolt is disposed through the opposed arms 214 and before the lockingbolt and locking nut 212 are tightened. For example, as shown, theopenings 226 can be elliptical and can have a major axis that is greaterthan an outside diameter of the locking bolt 210 and a minor axis thatis substantially equal to the outside diameter of the locking bolt.Accordingly, the first clamping member 202 can translate relative to thelocking bolt 210 only in the X and Z directions shown on the firstclamping member in FIG. 2D. By way of further example, the openings 226can be circular and can have an inside diameter that is greater than anoutside diameter of the locking bolt 210 such that the first clampingmember 202 can translate relative to the locking bolt in the X, Y, and Zdirections shown on the first clamping member in FIG. 2D.

The second clamping member 204 can include opposed arms 228 coupled toone another at a hinge portion 230. While a living hinge 230 is shown,it will be appreciated that any of a variety of hinge mechanisms can beused. For example, the opposed arms 228 can be rotatably coupled to oneanother about a pivot pin. The opposed arms 228 can each include amating portion 232 in which a recess 234 is formed for receiving asecond spinal fixation element 208. Each of the opposed arms 228 canalso include a main portion 236 disposed between the hinge portion 230and the mating portion 232. The opposed arms 228 can be positionable inan unlocked position in which a slot 238 defined between the mainportions 236 of the arms 228 has substantially parallel sidewalls and inwhich the second clamping member 204 is movable with respect to a secondspinal fixation element 208 disposed between the mating portions 232 ofthe arms 228. The opposed arms 228 can also be positionable in a lockedposition in which the main portions 236 of the arms are deflectedtowards one another about the hinge portion 230 and in which a secondspinal fixation element 208 disposed between the mating portions 232 ofthe arms is locked to the second clamping member 204 to resist orprevent rotation or sliding movement of the second spinal fixationelement relative to the second clamping member.

The mating portions 232 can define a recess 234 therebetween sizedand/or shaped according to the second spinal fixation element 208 towhich the second clamping member 204 is to be coupled. For example, adiameter of the recess 234 can be substantially equal to a diameter ofthe second spinal fixation element 208. Alternatively, the diameter ofthe recess 234 can be slightly less than the diameter of the secondspinal fixation element 208 to allow for a snap-fit engagement thatprovides tactile and/or audible feedback to the surgeon when the secondclamping member 204 “snaps” onto the second spinal fixation element. Asdiscussed further below, this feedback can be advantageous, particularlyin minimally-invasive revision surgery. As another alternative, thediameter of the recess 234 can be slightly greater than that of thesecond spinal fixation element 208 to which the connector 200 is to becoupled, with any play being taken up by the clamping action when thelocking bolt 210 and locking nut 212 are tightened. The second clampingmember 204 can thus be configured to couple to second spinal fixationelements of various sizes or shapes. In some embodiments, a plurality ofclamping members 204, each having recesses 234 with different sizes orshapes, can be provided as part of a kit to allow for selection of aclamping member sized and shaped appropriately for a particularapplication.

While the illustrated recess 234 forms a portion of a cylinder, it willbe appreciated that the recess can have various other shapes dependingon the shape of the second spinal fixation element 208 to which thesecond clamping member 204 is to be coupled. For example, in the case ofa second spinal fixation element 208 with a rectangular cross-section,the recess can have a corresponding rectangular shape. As shown in FIG.2H, the recess 234 can be defined by flat or planar sidewalls which, atleast in some instances, can provide increased surface contact for abroader range of fixation element sizes and shapes.

As shown in FIG. 2G, the recess 234 can have a longitudinal axis A3 thatextends perpendicular to a longitudinal axis A2 of the locking bolt 210when the locking bolt extends through the second clamping member 204.Thus, the longitudinal axis A3 of the recess 234 can be perpendicular toa rotation axis A2 about which the second clamping member 204 rotatesrelative to the locking bolt 210. The mating portions 232 of the arms228 can be configured to extend around any portion of the second spinalfixation element 208. In the illustrated embodiment, the arms 228collectively extend around approximately 180 degrees of thecircumference of the second spinal fixation element 208. In otherembodiments, the arms 228 can cover a greater or lesser extent of thecircumference of the second spinal fixation element 208. For example,the extent of coverage can be between about 90 degrees and about 270degrees of the circumference of the second spinal fixation element 208.

Coaxial openings 240 can be formed in the opposed arms 228 of the secondclamping member 204 such that the locking bolt 210 can extend throughthe opposed arms. The second clamping member 204 can be rotatable abouta longitudinal axis A2 of the locking bolt 210 when the locking bolt isdisposed through the opposed arms 214 and before the locking bolt andlocking nut 212 are tightened. One or more internal dimensions of theopenings 240 can be larger than corresponding external dimensions of thelocking bolt 210 to allow the second clamping member 204 to translate inone or more directions relative to the locking bolt when the lockingbolt is disposed through the opposed arms 228 and before the lockingbolt and locking nut 212 are tightened. For example, as shown, theopenings 240 can be elliptical and can have a major axis that is greaterthan an outside diameter of the locking bolt 210 and a minor axis thatis substantially equal to the outside diameter of the locking bolt.Accordingly, the second clamping member 204 can translate relative tothe locking bolt 210 only in the X and Z directions shown on the secondclamping member in FIG. 2D. By way of further example, the openings 240can be circular and can have an inside diameter that is greater than anoutside diameter of the locking bolt 210 such that the second clampingmember 204 can translate relative to the locking bolt in the X, Y, and Zdirections shown on the second clamping member in FIG. 2D.

The first clamping member 202 can include a planar upper surface 242that is configured to be substantially parallel to a planar lowersurface 244 of the second clamping member 204 when the first and secondclamping members are engaged with one another over the locking bolt 210.The first clamping member 202 can include a planar lower surface 246that extends at an oblique angle with respect to the planar uppersurface 242 of the first clamping member 202. The second clamping member204 can include a planar upper surface 248 that extends at an obliqueangle with respect to the planar lower surface 244 of the secondclamping member 204. A spherical or ellipsoid protrusion 250 can beformed on the lower surface 246 of the first clamping member 202 and canbe received in a corresponding spherical or ellipsoid recess 252 formedin the upper surface 248 of the second clamping member 204. The curvedinterface between the first and second clamping members 202, 204 canfacilitate limited-contact, gliding movement when rotating and/ortranslating the first and second clamping members with respect to oneanother. It will be appreciated that, in some embodiments, theprotrusion 250 can be formed on the second clamping member 204 and therecess 252 can be formed in the first clamping member 202.

While any of a variety of locking mechanisms can be used, in theillustrated embodiment, the locking mechanism includes a locking bolt210 and a locking nut 212. The locking bolt 210 can include a headportion 254 and an elongate shank portion 256. The head portion 254 canhave a faceted exterior surface to be gripped by a wrench to facilitatetightening or loosening of the locking bolt 210. Alternatively, or inaddition, the head portion 254 can include a female recess in which ascrewdriver or other instrument can be received to rotate and tighten orloosen the locking bolt 210. The shank 256 of the locking bolt 210 canbe threaded along its entire length or along only a portion of itslength. The threaded shank 256 can be received within the threadedinterior of the locking nut 212 such that rotation of the locking bolt210 relative to the locking nut in a first direction is effective todraw the nut towards the head portion 254 of the locking bolt andrelative rotation in a second, opposite direction is effective to urgethe locking nut away from the head portion of the locking bolt. At leasta portion of the locking nut 212 can be non-rotatably received withinthe second clamping member 204. For example, the locking nut 212 canhave an elliptical portion 258 configured to be received in theelliptical opening 240 of the lower arm of the second clamping member204. The major axis of the elliptical portion 258 of the locking nut 212can be less than the major axis of the elliptical opening 240, such thatthe second clamping member 204 can translate in at least one directionwith respect to the locking nut when the locking nut is receivedtherein.

The locking nut 212 can be configured to be received within the secondclamping member 204 such that the locking nut sits flush or sub-flushwith the lower planar surface 244 of the second clamping member or suchthat it sits proud as shown. While the head 254 of the locking bolt 210is shown as sitting proud of the upper planar surface 242 of the firstclamping member 202 in the illustrated embodiment, the head can bechamfered, countersunk, or otherwise configured to sit flush orsub-flush with the upper surface of the first clamping member whentightened. In some embodiments, the locking nut can be omitted and thelocking mechanism can include a locking screw configured to threadablyengage a threaded opening formed in one or more of the arms of the firstand/or second locking members (e.g., a lower arm of the second lockingmember).

In use, the spinal connector 200 can be positioned in a surgical site(e.g., using a minimally-invasive technique as described in detailbelow). A first spinal fixation element 206 can be positioned within therecess 220 of the first clamping member 202 and a second spinal fixationelement 208 can be positioned within the recess 234 of the secondclamping member 204. The first and second clamping members 202, 204 canbe translated and/or rotated with respect to one another and/or withrespect to the locking mechanism to place the first and second spinalfixation elements 206, 208 in the desired relative alignment. Themultiple degrees of freedom provided by the spinal connector 200 can beparticularly advantageous when the first and second spinal fixationelements 206, 208 are not parallel to one another. As the locking bolt210 is tightened, the first and second clamping members 202, 204 bend attheir respective hinge portions 216, 230 into their respective lockedconfigurations, clamping down on the first and second spinal fixationelements 206, 208 and locking them to the connector 200. At the sametime, the first and second clamping members 202, 204 are squeezed intofirm engagement with one another, resisting or preventing the first andsecond clamping members from rotating with respect to one another and/orfrom translating in one or more directions with respect to one another.Actuation of a single locking mechanism can thus be effective to (1)lock the first clamping member to a first spinal fixation element, (2)lock the second clamping member to a second spinal fixation element, (3)lock a rotational degree of freedom between the first and secondclamping members, and (4) lock one or more translational degrees offreedom between the first and second clamping members. This multiplefunctionality of locking onto multiple spinal fixation elements andlocking one or more degrees of freedom of the connector can beparticularly advantageous in minimally-invasive surgery, as access isonly required to a single locking mechanism and two or more functionscan be performed in a single step.

The spinal connector 200 can be coupled to the spinal fixation elements206, 208 in any of a variety of orientations. For example, the spinalconnector 200 can be coupled to first and second spinal fixationelements 206, 208 that substantially lie in a common coronal plane suchthat the locking bolt 210 extends along an anterior-posterior orsagittal axis of the patient. By way of further example, the spinalconnector 200 can be coupled to first and second spinal fixationelements 206, 208 that substantially lie in a common sagittal plane suchthat the locking bolt extends along a medial-lateral or transverse axisof the patient. The spinal connector 200 can also be coupled to thespinal fixation elements 206, 208 in any orientation between the abovetwo examples and at any point along the lengths of the spinal fixationelements. The first and second spinal fixation elements 206, 208 neednot lie in a common plane.

In the illustrated embodiment, the first and second spinal fixationelements 206, 208 are elongate spinal rods, though it will beappreciated that any of a variety of fixation elements can be usedinstead or in addition, such as bone plates. The first and second spinalfixation elements 206, 208 can be completely straight or can include oneor more bends, curves, joints, offsets, jogs, etc. as described above.

FIGS. 3A-3E illustrate another exemplary embodiment of a spinalconnector 300. The connector 300 generally includes a first spinalfixation element 302 and a connection assembly 304 for coupling thefirst spinal fixation element 302 to a second spinal fixation element306. The second spinal fixation element 306 can be apreviously-implanted spinal fixation element to which the connector 300is to be coupled or can be implanted with the connector 300 or as partof the same procedure as the connector 300. The connection assembly 304can include a locking mechanism for selectively locking an orientationof the first spinal fixation element 302 relative to the connectionassembly 304 and for locking a position and an orientation of theconnection assembly relative to the second spinal fixation element 306.As shown, the connection assembly 304 can include an upper clamping arm308, a lower clamping arm 310, a biasing element 312, and a lockingelement 314.

In the illustrated embodiment, the first and second spinal fixationelements 302, 306 are elongate spinal rods, though it will beappreciated that any of a variety of fixation elements can be usedinstead or in addition, such as bone plates. The first spinal fixationelement 302 can include a mating feature 318 formed on or coupled to afirst terminal end thereof configured to rotatably couple the firstspinal fixation element to the connection assembly 304. In theillustrated embodiment, the mating feature 318 is a ring-shapedstructure formed integrally with the first spinal fixation element 302.The mating feature 318 can include a central opening 320 configured toreceive the locking element therethrough such that a non-threadedportion of the locking element is disposed in the central opening 320and the first spinal fixation element 302 is freely rotatable about thelocking element until the locking element is tightened (e.g., rotatableabout a longitudinal axis of the locking element). Stated differently,the connection assembly 304 can be rotatable about a longitudinal axisA1 of the central opening 320. A second, opposite terminal end 324 ofthe first spinal fixation element 302 can be configured to facilitateminimally-invasive insertion of the first spinal fixation element. Forexample, the second terminal end 324 can be rounded, bulleted, tapered,etc. to allow for atraumatic tunneling of the first spinal fixationelement 302 subcutaneously from an insertion portal to a final implantedposition.

The first spinal fixation element 302 can be completely straight or caninclude one or more bends, curves, joints, offsets, jogs, etc. Forexample, the first spinal fixation element 302 can have an S-shaped orZ-shaped bend to provide clearance for patient anatomy or for a portion(e.g., a bone screw) of a fixation construct to which the connector 300is to be coupled. In the illustrated embodiment, the first spinalfixation element 302 includes a straight portion 326 joined by a curvedportion 328 to the mating feature 318. The curved portion 328 canprovide an offset such that the first spinal fixation element 302 canbend around a portion of the patient's anatomy or a portion of afixation construct to which the connector 300 is coupled. Accordingly, alow-profile construct can be formed, with the straight portion 326 ofthe first spinal fixation element 302 positioned as a natural extensionof the second spinal fixation element 306. It will thus be appreciatedthat the connector 300 can be clamped onto a previously-installed secondspinal fixation element 306, intermediate to first and second boneanchors securing the second spinal fixation element, without the firstspinal fixation element 302 interfering with the bone anchors. The firstspinal fixation element 302 can be rigid, can be bendable or malleable,or can include both rigid portions and bendable portions. Thus, in someembodiments, the contour of the first spinal fixation element 302 can beadjusted as needed for a particular procedure, either manually or withthe assistance of bending tools.

The upper clamping arm 308 can include a rectangular recess 330 in whicha corresponding rectangular protrusion 332 formed on the lower clampingarm 310 can be received such that the upper and lower clamping arms arehinged together and can pivot relative to one another. It will beappreciated that, in other embodiments, the above arrangement can bereversed such that the lower clamping arm 310 includes the recess 330and the upper clamping arm 308 includes the protrusion 332.

Each of the upper and lower clamping arms 308, 310 can also include amating portion 334 for receiving the second spinal fixation element 306.Together, the mating portions 334 of the upper and lower clamping arms308, 310 can define a recess 336 therebetween sized and/or shapedaccording to the second spinal fixation element 306 to which theconnector 300 is to be coupled. For example, a diameter of the recess336 can be substantially equal to a diameter of the second spinalfixation element 306. Alternatively, the diameter of the recess 336 canbe slightly less than the diameter of the second spinal fixation element306 to allow for a snap-fit engagement that provides tactile and/oraudible feedback to the surgeon when the connector 300 “snaps” onto thesecond spinal fixation element 306. As discussed further below, thisfeedback can be advantageous, particularly in minimally-invasiverevision surgery. As another alternative, the diameter of the recess 336can be slightly greater than that of the second spinal fixation element306, with any play being taken up by the clamping action when thelocking element 314 is tightened. The connector 300 can thus beconfigured to couple to second spinal fixation elements of various sizesor shapes. In some embodiments, a plurality of connectors 300, eachhaving recesses 336 with different sizes or shapes, can be provided aspart of a kit to allow for selection of a connector sized and shapedappropriately for a particular application.

While the illustrated recess 336 forms a portion of a cylinder, it willbe appreciated that the recess can have various other shapes dependingon the shape of the second spinal fixation element 306 to which theconnector 300 is to be coupled. For example, in the case of a secondspinal fixation element 306 with a rectangular cross-section, the recess336 can have a corresponding rectangular shape.

The recess 336 can have a longitudinal axis A2 that extendsperpendicular to the longitudinal axis A1 of the central opening 320 andperpendicular to a longitudinal axis of the locking element 314. Thus,the longitudinal axis A2 of the recess 336 can be perpendicular to arotation axis about which the first spinal fixation element 302 rotatesrelative to the connection assembly 304. In such embodiments, when asecond spinal fixation element 306 is received in the recess 336, thefirst spinal fixation element 302 can be rotatable about an axisperpendicular to a longitudinal axis of the second spinal fixationelement 306. The mating portions 334 of the upper and lower clampingarms 308, 310 can be configured to extend around any portion of thesecond spinal fixation element 306. In the illustrated embodiment, theclamping arms 308, 310 collectively extend around approximately 240degrees of the circumference of the second spinal fixation element 306.In other embodiments, the clamping arms 308, 310 can cover a greater orlesser extent of the circumference of the second spinal fixation element306. For example, the extent of coverage can be between about 90 degreesand about 270 degrees of the circumference of the second spinal fixationelement 306.

The biasing element 312 can be disposed between the upper and lowerclamping arms 308, 310 and can be configured to bias the arms towards aclamped or partially clamped position. Accordingly, the diameter of therecess 336 defined between the arms 308, 310 can increase as the armsare spread apart against the bias of the biasing element 312 when aspinal fixation element 306 is inserted through an open end of theclamp. Once the spinal fixation element 306 clears the leading ends ofthe arms 308, 310 and is fully-disposed within the recess 336, thebiasing element 312 can cause the hinged portion of the arms to spreadapart, closing the mating portions 334 of the arms around the spinalfixation element, thereby providing a “snap fit” engagement with tactileand/or audible feedback to the user.

In the illustrated embodiment, the biasing element is a wave spring orwasher 312. The washer 312 can be bent in one or more planes and caninclude a central opening through which the locking element 314 can bereceived. The washer 312 can be formed from a flexible and resilientmaterial configured to deform to the shape of a flat washer when anexternal force (e.g., the force of the spinal fixation element 306 beingintroduced into the open end of the clamp) is applied and to spring backto the wave shape shown in FIG. 3B when the external force is removed.

The upper and lower clamping arms 308, 310 can include openings 338 thatare coaxial with one another and with the central opening of the biasingelement 312 such that the locking element 314 can extend through theclamping arms and through the biasing element.

While any of a variety of locking elements can be used, in theillustrated embodiment, the locking element is a locking screw 314. Thelocking screw 314 can include a head portion 340 and an elongate shankportion 342. The head portion 340 can include a driving interface (e.g.,a female recess 344 in which a screwdriver or other instrument can bereceived) to facilitate rotation and tightening or loosening of thelocking screw 314. The shank 342 of the locking screw 314 can bethreaded along its entire length or along only a portion of its length.In some embodiments, a section of the shank 342 immediately distal tothe head portion 340 can be left unthreaded to allow the mating feature318 of the first spinal fixation element 302 to rotate freely about thelocking screw 314 until the locking screw is tightened. At least aportion of the opening 338 formed in the lower clamping arm 310 can bethreaded and can be configured to threadably engage a threaded portionof the shank 342. Accordingly, rotation of the locking screw 314relative to the lower clamping arm 310 in a first direction can beeffective to draw the upper and lower clamping arms 308, 310 togetherand relative rotation in a second, opposite direction can be effectiveto allow the upper and lower clamping arms to move apart (e.g., underthe bias of the biasing element 312). The mating feature 318 of thefirst spinal fixation element 302 can include a recess 346 sized toreceive the head 340 of the locking screw 314 such that the lockingscrew is countersunk in the mating feature.

The connector 300 can be positionable in an unlocked configuration inwhich the locking screw 314 is not tightened, the upper and lowerclamping arms 308, 310 are movable with respect to the second spinalfixation element 306 disposed between the mating portions thereof, andthe first spinal fixation element 302 is freely rotatable about thelocking screw. The connector 300 can also be positionable in a lockedconfiguration by tightening the locking screw 314 such that a secondspinal fixation element 306 disposed between the mating portions of thearms 308, 310 is locked to resist or prevent rotation or slidingmovement of the second spinal fixation element 306 relative to theconnector 300 and such that the first spinal fixation element 302 is notfreely rotatable relative to the connection assembly 304.

In use, the spinal connector 300 can be positioned in a surgical site(e.g., using a minimally-invasive technique as described in detailbelow). A previously-placed second spinal fixation element 306 can bepositioned within the recess 336 defined between the upper and lowerclamping arms 308, 310 and the connection assembly 304 can be moved to adesired position and/or orientation with respect to the second spinalfixation element 306. In addition, the first spinal fixation element 302can be rotated to a desired position. As the locking element 314 istightened, the upper and lower clamping arms 308, 310 can clamp down onthe second spinal fixation element 306 to clamp the connection assembly304 thereto and lock the position and orientation of the connectionassembly relative to the second spinal fixation element. At the sametime or at substantially the same time, the mating feature 318 of thefirst spinal fixation element 302 can be squeezed into firm engagementwith the upper clamping arm 308 to lock the rotational position of thefirst spinal fixation element 302 relative to the connection assembly304. Actuation of a single locking mechanism can thus be effective to(1) lock an orientation of a first spinal fixation element relative tothe connection assembly and (2) lock a position and an orientation ofthe connector relative to a second spinal fixation element. Thismultiple functionality of locking onto a second spinal fixation elementand locking one or more degrees of freedom of the connector can beparticularly advantageous in minimally-invasive surgery, as access isonly required to a single locking mechanism and two or more functionscan be performed in a single step.

The spinal connector 300 can be coupled to the second spinal fixationelement 306 in any of a variety of orientations. For example, the spinalconnector 300 can be coupled to the second spinal fixation element 306such that the driving interface 344 of the locking screw 314 faces in aposterior direction relative to the patient and such that the lockingscrew is advanced along an anterior-posterior axis to lock theconnector. By way of further example, the spinal connector 300 can becoupled to the second spinal fixation element 306 such that the drivinginterface 344 of the locking screw 314 faces in a medial or lateraldirection relative to the patient and the locking screw is advancedalong a medial-lateral axis to lock the connector. The spinal connector300 can also be coupled to the second spinal fixation element 306 in anyorientation between the above two examples and at any point along alength of the second spinal fixation element.

FIGS. 4A-4E illustrate another exemplary embodiment of a spinalconnector 400. The connector 400 generally includes a first spinalfixation element 402 and a connection assembly 404 for coupling thefirst spinal fixation element 402 to a second spinal fixation element406. The second spinal fixation element 406 can be apreviously-implanted spinal fixation element to which the connector 400is to be coupled or can be implanted with the connector 400 or as partof the same procedure as the connector 400. The connection assembly 404can include a locking mechanism for selectively locking an orientationof the first spinal fixation element 402 relative to the connectionassembly 404 and for locking a position and an orientation of theconnection assembly relative to the second spinal fixation element 406.As shown, the connection assembly 404 can include a clamping member 408,a washer 410, and a locking element 412.

In the illustrated embodiment, the first and second spinal fixationelements 402, 406 are elongate spinal rods, though it will beappreciated that any of a variety of fixation elements can be usedinstead or in addition, such as bone plates. The first spinal fixationelement 402 can include a mating feature 418 formed on or coupled to afirst terminal end thereof configured to rotatably couple the firstspinal fixation element to the connection assembly 404. In theillustrated embodiment, the mating feature 418 is a ring-shapedstructure formed integrally with the first spinal fixation element 402.The mating feature 418 can include a central opening 420 configured toreceive a stud portion 414 of the clamping member 408 therethrough suchthat the mating feature is rotatable about the stud portion (e.g., abouta longitudinal axis of the stud portion) until the locking element 412is tightened. Stated differently, the clamping member 408 can berotatable about a longitudinal axis A1 of the central opening 420. Theclamping member 408 can also be rotatable about a transverse axis A2 ofthe central opening 420. In particular, the central opening 420 can beconfigured to allow positioning of the stud portion 414 therein at aplurality of angles. Thus, the stud portion 414 can be disposed in thecentral opening 420 such that a longitudinal axis of the stud portion iscollinear with a longitudinal axis of the central opening, or such thatthe longitudinal axis of the stud portion extends at an oblique anglewith respect to the longitudinal axis of the central opening. Tofacilitate such positioning, for example, the central opening 420 can beelongated in one or more directions such that the central opening isnon-circular. By way of further example, the central opening 420 caninclude one or more lateral reliefs or cut-outs 416 to allow forangulation of the stud portion 414 within the central opening 420.

A second, opposite terminal end 424 of the first spinal fixation element402 can be configured to facilitate minimally-invasive insertion of thefirst spinal fixation element. For example, the second terminal end 424can be rounded, bulleted, tapered, etc. to allow for atraumatictunneling of the first spinal fixation element 402 subcutaneously froman insertion portal to a final implanted position.

The first spinal fixation element 402 can be completely straight or caninclude one or more bends, curves, joints, offsets, jogs, etc. Forexample, the first spinal fixation element 402 can have an S-shaped orZ-shaped bend to provide clearance for patient anatomy or for a portion(e.g., a bone screw 422) of a fixation construct to which the connector400 is to be coupled. In the illustrated embodiment, the first spinalfixation element 402 includes a straight portion 426 joined by a curvedportion 428 to another straight portion 430 where the mating feature 418is formed. The curved portion 428 can provide an offset such that thefirst spinal fixation element 402 can bend around a portion of thepatient's anatomy or a portion of a fixation construct to which theconnector 400 is coupled. Accordingly, a low-profile construct can beformed, with the straight portion 426 of the first spinal fixationelement 402 positioned as a natural extension of the second spinalfixation element 406. It will thus be appreciated that the connector 400can be clamped onto a previously-installed second spinal fixationelement 406, intermediate to first and second bone anchors securing thesecond spinal fixation element, without the first spinal fixationelement 402 interfering with the bone anchors. The first spinal fixationelement 402 can be rigid, can be bendable or malleable, or can includeboth rigid portions and bendable portions. Thus, in some embodiments,the contour of the first spinal fixation element 402 can be adjusted asneeded for a particular procedure, either manually or with theassistance of bending tools.

As shown in FIGS. 4B-4C, the mating feature 418 can include a lowersurface 432 configured to engage a shoulder 434 formed on the clampingmember 408 and an upper surface 436 configured to engage the washer 410.The upper surface 436 can include one or more surface features that canbe engaged by corresponding surface features of the washer 410 to lock arelative angle between the stud portion 414 of the clamping member 408and the mating feature 418 about the transverse axis A2 of the centralopening. In the illustrated embodiment, the surface features includefirst and second cylindrical protrusions 438 with a plurality of teethformed thereon. While teeth are shown, it will be appreciated that anyof a variety of surface features can be used, such as ratchet steps,roughened or textured contact surfaces, etc. The teeth of theprotrusions 438 can mesh with corresponding teeth formed in recesses 440of the washer 410 in which the protrusions can be received. The teethcan extend radially-outward from the pivot axis A2 about which themating feature 418 can rotate relative to the stud portion 414 when thestud portion is disposed within the central opening 420 of the matingfeature. It will be appreciated that, in other embodiments, theprotrusions 438 can be formed on the washer 410 and the recesses 440 canbe formed in the mating feature 418.

The clamping member 408 can include opposed arms 442 coupled to oneanother at a hinge portion 444. While a living hinge 444 is shown, itwill be appreciated that any of a variety of hinge mechanisms can beused. For example, the opposed arms 442 can be rotatably coupled to oneanother about a pivot pin. The opposed arms 442 can each include amating portion 446 for receiving the second spinal fixation element 406.Each of the opposed arms 442 can also include a main portion 450disposed between the hinge portion 444 and the mating portion 446. Theopposed arms 442 can be positionable in an unlocked position in which aslot 452 formed between the main portions 450 of the arms hassubstantially parallel sidewalls and in which the clamping member 408 ismovable with respect to a second spinal fixation element 406 disposedbetween the mating portions 446 of the arms. The opposed arms 442 canalso be positionable in a locked position in which the main portions 450of the arms are deflected towards one another about the hinge portion444 and in which a second spinal fixation element 406 disposed betweenthe mating portions 446 of the arms is locked to the clamping member 408to resist or prevent rotation or sliding movement of the second spinalfixation element 406 relative to the clamping member 408. The outersidewalls 454 of the arms 442 can be tapered such that advancing thelocking element 412 distally towards the shoulder 434 of the clampingmember 408 squeezes the arms together, moving them towards the lockedposition. The hinge portions 444 of the arms 442 can be resilient suchthat retracting the locking element 412 proximally away from theshoulder 434 of the clamping member 408 allows the arms to spread apartand move towards the unlocked position.

The mating portions 446 can define a recess 448 therebetween sizedand/or shaped according to the spinal fixation element to which theclamping member 408 is to be coupled. For example, a diameter of therecess 448 can be substantially equal to a diameter of the second spinalfixation element 406. Alternatively, the diameter of the recess 448 canbe slightly less than the diameter of the second spinal fixation element406 to allow for a snap-fit engagement that provides tactile and/oraudible feedback to the surgeon when the clamping member 408 “snaps”onto the second spinal fixation element 406. As discussed further below,this feedback can be advantageous, particularly in minimally-invasiverevision surgery. As another alternative, the diameter of the recess 448can be slightly greater than that of the second spinal fixation element406, with any play being taken up by the clamping action when thelocking element 412 is tightened. The clamping member 408 can thus beconfigured to couple to spinal fixation elements of various sizes orshapes. In some embodiments, a plurality of clamping members 408, eachhaving recesses 448 with different sizes or shapes, can be provided aspart of a kit to allow for selection of a clamping member sized andshaped appropriately for a particular application.

While the illustrated recess 448 forms a portion of a cylinder, it willbe appreciated that the recess can have various other shapes dependingon the shape of the second spinal fixation element 406 to which theconnector 400 is to be coupled. For example, in the case of a secondspinal fixation element 406 with a rectangular cross-section, the recess448 can have a corresponding rectangular shape.

The recess 448 can have a longitudinal axis A3 that extendsperpendicular to a longitudinal axis of the stud portion 414 and to thelongitudinal axis of the locking element 412. Thus, the longitudinalaxis A3 of the recess 448 can be perpendicular to an axis along whichthe locking element 412 is advanced. The mating portions 448 of the arms442 can be configured to extend around any portion of the second spinalfixation element 406. In the illustrated embodiment, the arms 442collectively extend around approximately 240 degrees of thecircumference of the second spinal fixation element 406. In otherembodiments, the arms can cover a greater or lesser extent of thecircumference of the second spinal fixation element 406. For example,the extent of coverage can be between about 90 degrees and about 270degrees of the circumference of the second spinal fixation element 406.

While any of a variety of locking elements can be used, in theillustrated embodiment, the locking element comprises a locking nut 412.At least a portion of the locking nut 412 can include a threadconfigured to threadably engage a corresponding thread formed on thestud portion 414 of the clamping member 408. Accordingly, rotation ofthe locking nut 412 relative to the stud portion 414 in a firstdirection can be effective to urge the locking nut towards the shoulderportion 434 of the clamping member 408, compressing the washer 410 andthe mating feature 418 therebetween, and relative rotation in a second,opposite direction can be effective to move the locking nut away fromthe shoulder portion of the clamping member.

The connector 400 can be positionable in an unlocked configuration inwhich the locking nut 412 is not tightened, the mating feature 418 andthe first spinal fixation element 402 are rotatable about the axis A1and the axis A2 relative to the stud portion 414 of the clamping member408, and the clamping member is rotatable and slidable with respect to asecond spinal fixation element 406 disposed between the mating portions446 thereof. The connector 400 can also be positionable in a lockedconfiguration by tightening the locking nut 412 such that a secondspinal fixation element 406 disposed between the mating portions 446 islocked to resist or prevent rotation or sliding movement of the secondspinal fixation element relative to the connector 400 and such that themating feature 418 and the first spinal fixation element 402 are notfreely rotatable relative to the stud portion 414 about the axis A1 orthe axis A2.

In use, the spinal connector 400 can be positioned in a surgical site(e.g., using a minimally-invasive technique as described in detailbelow). A previously-placed second spinal fixation element 406 can bepositioned within the recess 448 defined between the arms 442 of theclamping member 408 and the clamping member can be moved to a desiredposition and/or orientation with respect to the second spinal fixationelement 406. In addition, the first spinal fixation element 402 can berotated to a desired position about the axis A1 and/or the axis A2. Asthe locking element 412 is tightened, the arms 442 can clamp down on thesecond spinal fixation element 406 to lock the position and orientationof the clamping member 408 relative to the second spinal fixationelement. At the same time, the mating feature 418 of the first spinalfixation element 402 can be squeezed into firm engagement with theshoulder 434 of the clamping member 408 and the teeth of the washer 410,resisting or preventing the first spinal fixation element 402 fromrotating about the axis A1 or the axis A2 with respect to the studportion 414. Actuation of a single locking mechanism can thus beeffective to (1) lock the position and orientation of the connectorrelative to a second spinal fixation element and (2) lock first andsecond rotational degrees of freedom of the first spinal fixationelement relative to the second spinal fixation element. This multiplefunctionality of locking onto a second spinal fixation element andlocking one or more degrees of freedom of the connector can beparticularly advantageous in minimally-invasive surgery, as access isonly required to a single locking mechanism and two or more functionscan be performed in a single step.

The spinal connector 400 can be coupled to the second spinal fixationelement 406 in any of a variety of orientations. For example, the spinalconnector 400 can be coupled to the second spinal fixation element 406such that the longitudinal axis of the stud portion 414 extends in ananterior-posterior direction relative to the patient. By way of furtherexample, the spinal connector 400 can be coupled to the second spinalfixation element 406 such that the longitudinal axis of the stud portionextends in a medial-lateral direction relative to the patient. Thespinal connector 400 can also be coupled to the second spinal fixationelement 406 in any orientation between the above two examples and at anypoint along a length of the second spinal fixation element.

The first spinal fixation element 406 can include one or more couplingfeatures for attaching the first spinal fixation element to an insertioninstrument. For example, the first spinal fixation element 402 caninclude a coupling feature 456 that extends along a longitudinal axis ofthe straight portion 430, as shown in FIG. 4A. By way of furtherexample, the first spinal fixation element 402 can include a couplingfeature 456′ that extends at an oblique angle with respect to alongitudinal axis of the straight portion 430, as shown in FIG. 4E.While not shown, the spinal connectors 100, 200, 300 described above caninclude a similar coupling feature.

FIGS. 5A-5D illustrate another exemplary embodiment of a spinalconnector 500. Except as indicated below, the structure and operation ofthe spinal connector 500 is substantially identical to that of thespinal connector 400 discussed above. Accordingly, a detaileddescription of said structure and operation is omitted here for the sakeof brevity. The mating feature 518 of the spinal connector 500 isdisposed in-line with the adjacent rod portion 530, as opposed toextending laterally therefrom as in the spinal connector 400. This canallow the connector 500 to be positioned such that the second spinalfixation element 506 is disposed directly beneath the first spinalfixation element 502, as shown in FIG. 5C. The connector 500 can also bepositioned with respect to the second spinal fixation element 506 asshown in FIG. 5D, such that the longitudinal axis of the mating feature518 is perpendicular to the longitudinal axis of a bone anchor 522coupled to the second spinal fixation element.

In addition, the mating feature 518 and the stud portion 514 of theclamping member 508 are taller in the spinal connector 500 than in thespinal connector 400. This can provide sufficient clearance space forthe first spinal fixation element 502 to extend over a bone anchor 522holding the second spinal fixation element 506 in place without thefirst spinal fixation element interfering with the bone anchor.

FIGS. 6A-6G schematically illustrate a method of using a spinalconnector of the type disclosed herein to extend a fixation construct toan adjacent vertebral level as part of a minimally-invasive revisionsurgery.

FIG. 6A illustrates a portion of a spinal column of a patient in which afirst spinal fixation element (e.g., an elongate fixation rod R1) hasbeen coupled to a superior vertebra V1 and an adjacent inferior vertebraV2 using pedicle screws S1, S2. The fixation construct is implantedbeneath the patient's skin D.

As shown in FIG. 6B, a first minimally invasive pathway P1 can be formedto access a third vertebra V3 inferior to the vertebra V2 and adjacentto the vertebra V2. In some embodiments, a percutaneous access devicecan be used to provide the minimally-invasive pathway P1.

As shown in FIG. 6C, a pedicle screw S3 can be delivered through theminimally-invasive pathway P1 and can be implanted in the vertebra V3.Any of a variety of known techniques can be used to install the pediclescrew S3. For example, the screw S3 can be delivered over a guidewiredocked in a pedicle of the vertebra V3 along a predetermined screwtrajectory. The screw S3 can include one or more rod reduction tabsextending therefrom.

As shown in FIG. 6D, a second minimally-invasive pathway P2 can beformed to access a section of the rod R1 between the pedicle screws S1,S2. In some embodiments, a percutaneous access device can be used toprovide the minimally-invasive pathway P2.

As shown in FIG. 6E, a spinal connector SC of the type described herein,including a spinal fixation element R2 thereof, can be passed throughthe second minimally-invasive pathway P2. The spinal connector SC can beadvanced through the pathway P2, with a rounded or bulleted leading tipof the spinal fixation element R2 being tunneled subcutaneously throughthe rod-reduction tabs to position a portion of the spinal fixationelement R2 within a rod-receiving recess of the pedicle screw S3.

As shown in FIG. 6F, a clamping portion or rod-receiving portion of thespinal connector SC can be coupled to the first spinal fixation elementR1 at a position between the first and second pedicle screws S1, S2. Oneor more degrees of freedom of the spinal connector SC can be adjusted asneeded to achieve the desired alignment. The spinal connector SC can beconfigured to provide tactile and/or audible feedback as described above(e.g., by “snapping” onto the spinal fixation element R1) to give thesurgeon confidence that the connector is securely coupled to the spinalfixation element R1. Once the connector is in the desired position, orat any other appropriate time, a set screw or other locking element canbe inserted through the first minimally-invasive pathway P1 to securethe spinal fixation element R2 to the pedicle screw S3. The set screwcan also be preassembled with the pedicle screw S3 and then tightenedonce the connector and the spinal fixation element R2 are in the desiredposition. Before or after securing the spinal fixation element R2 to thepedicle screw S3, a driver or other instrument can be inserted throughthe second minimally-invasive pathway P2 to tighten or otherwise actuatea locking element of the spinal connector SC. As detailed above, asingle locking element and a single actuation movement (e.g., rotationof a locking nut as shown) can be effective to cause the connector SC toclamp down on the spinal fixation element R1 and to lock any degrees offreedom of the spinal fixation element R2 with respect to the rest ofthe connector and, by extension, the spinal fixation element R1.

As shown in FIG. 6G the rod reduction tabs of the pedicle screw S3 canbe removed and the first and second minimally-invasive pathways P1, P2can be closed. The spinal connector SC can be left implanted in thepatient to extend the previously-installed construct to an adjacentvertebral level as shown.

It should be noted that any ordering of method steps implied by thedrawings or description herein is not to be construed as limiting thedisclosed methods to performing the steps in that order. Rather, thevarious steps of each of the methods disclosed herein can be performedin any of a variety of sequences. In addition, as the described methodsare merely exemplary embodiments, various other methods that includeadditional steps or include fewer steps are also within the scope of thepresent invention.

It will be appreciated that the spinal connectors disclosed herein canbe used in any of a variety of methods that differ in one or moreaspects from that described above. For example, the initially-placedconstruct need not be coupled to adjacent vertebrae, and need not belimited to only two vertebral levels as shown. By way of furtherexample, an existing construct can be extended in a superior directioninstead of an inferior direction as shown. As yet another example, anexisting construct can be extended to a non-adjacent vertebra, and/or tomore than one additional vertebra. While a procedure is shown withrespect to a human spine, the connectors herein can be used to couplefixation elements to any bone, bones, or other structures in any livingor non-living subject (e.g., humans, animals, machines, etc.). The abovemethod need not necessarily be performed as part of a revision surgerywith a previously-implanted construct, but rather can be used to extenda construct implanted as part of the same procedure in which the spinalconnector is implanted. While pedicle screws and fixation rods areshown, it will be appreciated that various other hardware can beemployed, such as bone hooks, wires, tethers, etc. and can be implantedin regions other than the pedicles. The method described above is notlimited to use in minimally-invasive surgery, but rather can be used inopen surgical procedures or in hybrid procedures.

While a spinal connector of the type shown in FIG. 5A is shown in theillustrated method, any of the spinal connectors disclosed herein can beused instead or in addition with any necessary modifications beingapparent to one skilled in the art having read the above disclosure. Forexample, the connector 200 shown in FIG. 2A can be inserted through theminimally-invasive pathway P2, either before or after coupling theconnector 200 to a rod R2 to be placed between the connector and thepedicle screw S3. By way of further example, the connector 100 shown inFIG. 1A, the connector 300 shown in FIG. 3A, or the connector 400 shownin FIG. 4A can be used in a manner similar to that shown.

In some embodiments, the rod R2 can be inserted first and then thespinal connector SC inserted subsequently. The various components of thespinal connector SC can be assembled entirely outside of the patient,entirely inside of the patient, or any combination thereof. In someembodiments, the rod R2 can be inserted in a direction opposite to thatshown. For example, the rod R2 can be inserted through the pathway P1and the leading end advanced subcutaneously in a superior direction intoposition adjacent the rod R1. The spinal connector SC can then be passedthrough the pathway P2 and used to couple the rods R1, R2 to oneanother. While bent or curved rods are shown, the rod can also bestraight and pivoting polyaxial or uniplanar head of the screw S3 can berelied upon to clear the preexisting construct. In some embodiments, therod R2 and the spinal connector SC can be implanted first and the screwS3 can be implanted thereafter. This can be the case particularly if thescrew S3 is a side-loading screw. The spinal connector SC can be coupledto the rod R1 intermediate the screws S1, S2 as shown, or can be coupledto an end portion of the rod R1 that is not intermediate the screws S1,S2.

The spinal connectors disclosed herein can be formed from any of avariety of materials, such as nickel, titanium, stainless steel,polymers, ceramics, carbon fiber, etc. One or more components of thespinal connectors disclosed herein can be formed from a radiopaquematerial to facilitate visualization under fluoroscopy and other imagingtechniques. Other components of the devices disclosed herein can beformed from a radiolucent material so as not to interfere withvisualization of other components or bone structures.

Although the invention has been described by reference to specificembodiments, it should be understood that numerous changes may be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedescribed embodiments, but that it have the full scope defined by thelanguage of the following claims.

The invention claimed is:
 1. A spinal fixation method, comprising:forming a first minimally-invasive pathway to access a first vertebra;delivering a screw through the first minimally-invasive pathway;implanting the screw in the first vertebra; forming a secondminimally-invasive pathway to access a first spinal fixation elementcoupled to at least one other vertebra; delivering a second spinalfixation element and a spinal connector coupled thereto through thesecond minimally-invasive pathway, the second spinal fixation elementincluding an opening configured to receive a rigidly affixed portion ofthe spinal connector therethrough; moving the spinal connector relativeto the second spinal fixation element about one or more degrees offreedom to position at least a portion of the second spinal fixationelement in engagement with the screw; and actuating a locking element ofthe spinal connector to lock the spinal connector to the first spinalfixation element and to lock the one or more degrees of freedom.
 2. Themethod of claim 1, wherein moving the spinal connector comprises movingthe second spinal fixation element subcutaneously into engagement withthe screw.
 3. The method of claim 1, wherein the first spinal fixationelement is a previously-implanted spinal fixation element.
 4. The methodof claim 1, wherein the spinal connector comprises a clamp having therigidly affixed portion received in the opening of the second spinalfixation element, and wherein the one or more degrees of freedomcomprises a first rotational degree of freedom by which the secondspinal fixation element is rotatable with respect to the clamp about alongitudinal axis of the opening and a second rotational degree offreedom by which the second spinal fixation element is rotatable withrespect to the clamp about a transverse axis of the opening.
 5. Themethod of claim 1, wherein the spinal connector comprises a clamp havingthe rigidly affixed portion received in the opening of the second spinalfixation element, and wherein moving the spinal connector comprisespivoting the rigidly affixed portion about a longitudinal axis of theopening and about a transverse axis of the opening.
 6. The method ofclaim 1, wherein the spinal connector comprises a clamp having therigidly affixed portion received in the opening of the second spinalfixation element and a washer disposed around the stud portion, andwherein moving the spinal connector comprises engaging surface featuresformed on the washer with corresponding surface features formed on themating feature.
 7. The method of claim 1, wherein the spinal connectorcomprises first and second arms coupled to one another at a hingeportion and having tapered outer surfaces, and wherein actuating thelocking element comprises advancing a locking nut along the first andsecond arms to squeeze the arms together.
 8. The method of claim 1,wherein actuating the locking element consists only of rotating a singlelocking element.
 9. The method of claim 1, further comprisingpositioning the second spinal fixation element such that the secondspinal fixation element extends around a bone anchor secured to thefirst spinal fixation element.
 10. The method of claim 1, furthercomprising attaching the spinal connector to the first spinal fixationelement at a location intermediate first and second bone anchorssecuring the first spinal fixation element to bone.
 11. A spinalfixation method, comprising: forming a first minimally-invasive pathwayto access a first vertebra; delivering a screw through the firstminimally-invasive pathway; implanting the screw in the first vertebra;forming a second minimally-invasive pathway to access a first spinalfixation element coupled to at least one other vertebra; delivering asecond spinal fixation element through the first minimally-invasivepathway to position a portion of the second spinal fixation element inthe second minimally-invasive pathway; inserting a spinal connectorthrough the second minimally-invasive pathway and coupling the spinalconnector to the first and second spinal fixation elements by actuatinga single, preassembled locking element to cause the spinal connector toclamp down on the first spinal fixation element and to lock any degreesof freedom of the second spinal fixation element with respect to thespinal connector and the first spinal fixation element using a singlemovement, the second spinal fixation element including an openingconfigured to receive a rigidly affixed portion of the spinal connectortherethrough; and securing the second spinal fixation element to thescrew.
 12. The method of claim 11, wherein coupling the spinal connectorfurther comprises: adjusting one or more degrees of freedom of thespinal connector to position the spinal connector with respect to thefirst and second spinal fixation elements.
 13. A spinal fixation method,comprising: clamping a spinal connector having a first spinal fixationelement coupled thereto onto a second spinal fixation element, the firstspinal fixation element including an opening configured to receive aportion of the spinal connector therethrough; and rotating a lockingelement to drive first and second opposed shoes radially outwardrelative to a rotation axis of the locking element to simultaneouslylock the spinal connector to the second spinal fixation element and tolock one or more degrees of freedom between the spinal connector and thefirst spinal fixation element; wherein a first longitudinal axis of thefirst spinal fixation element is obliquely angled relative to a secondlongitudinal axis of the second spinal fixation element about alongitudinal axis of the spinal connector that is perpendicular to eachof the first and second longitudinal axes.
 14. A spinal fixation method,comprising: clamping a spinal connector having a first spinal fixationelement coupled thereto onto a second spinal fixation element; androtating a locking element to drive first and second opposed shoesradially outward relative to a rotation axis of the locking element tosimultaneously lock the spinal connector to the second spinal fixationelement and to lock one or more degrees of freedom between the spinalconnector and the first spinal fixation element; wherein a firstlongitudinal axis of the first spinal fixation element is obliquelyangled relative to a second longitudinal axis of the second spinalfixation element about a longitudinal axis of the spinal connector thatis perpendicular to each of the first and second longitudinal axes, andwherein the first spinal fixation element is constrained to move withina plane perpendicular to the longitudinal axis of the spinal connector.